If the brain processes information in an approximately modular fashion, how do specialized modular circuits that process radically different types of information cooperate in order to solve common problems? The present proposal seeks to investigate an instance of this general question by focusing on form-motion interactions in the visual pathway. It is important to understand how disparate and perhaps distant neuronal circuits, processing different types of information such as shape and motion, come to interact. Until fairly recently, form analysis was thought to proceed along the ventral pathway in relative isolation of dorsal motion processing. For instance, it was thought that form analysis played little role in solving the correspondence problem in apparent motion. Recent psychophysical data and evidence from functional magnetic resonance imaging (fMRI), however, suggest that motion and form are processed together at the earliest stages of visual processing, and continue to interact even at the highest levels of representation. The goal of the proposed research is to determine the neural circuitry involved in form-motion interactions in the visual pathway, and to uncover the nature of the 3D representations of form that are attained rapidly from visual input, which may then guide the analysis of 3D motion in a scene. To this end, several fMRI experiments are proposed to address when, how, and where form and motion interact in the visual system. The primary stimulus probe will be a type of apparent motion developed by the PI, where two discrete images shown in succession appear to be smoothly animated. Theoretical and empirical evidence support the view that this type of stimulus involves a very rapid interaction between the form and motion processing pathways. Taken together, these studies will provide important insights into the specific operations engaged when circuits known to process different types of information interact. Such insights may ultimately aid in the development of more effective cognitive rehabilitation strategies for the treatment of brain injury. Without an understanding of how modules cooperate, science and medicine cannot adequately repair brains where cooperation among modular circuitry has broken down.